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Speedometer/Odometer Quit

Joined
12 March 2003
Messages
74
Location
Severna Park Maryland
Both the speedometer and odometer on our '94 5sp. stopped functioning. Although it seems electrical, I see no fuse/circuit beaker that controls these. Thoughts please. Thank you!
 
This same thing just happened to my '92 manual over the weekend during the Mideast NSX Meet in Raleigh.
Starts wigging out after about an hour and a half of driving/cruising on the highway. But works fine in the morning/next day after things have cooled off.

VSS for sure.
 
Almost certainly the VSS on the top of the transmission. Can be replaced fairly easily after gaining some room to work from the top by removing the airbox.

The VSS internal potting seems to melt into a smelly mess and makes it sensitive to temperature, so when the car is hot the VSS starts acting up and then works again after cooling down. You can get a very cheap Chinesium aftermarket VSS from Amazon/etc. that has the same fitment and will work perfectly fine at <1/10 the price of OEM.
 
i had this wiggle of the speedo a few months ago. now my odo works but my speedo doesnt. doesnt bother me much as ive gotten really good at judging speed based on RPM in 5th gear
 
i had this wiggle of the speedo a few months ago. now my odo works but my speedo doesnt. doesnt bother me much as ive gotten really good at judging speed based on RPM in 5th gear

If the odometer works; but, the speedometer doesn't the problem is not the VSS. The bad news is the problem may be in the speedometer drive circuit which may be an indication of failing capacitors. Failing capacitors may result in permanent damage to the circuit board and create other problems in the cluster. There has been at least one report of a fire in an NSX resulting from a short circuit in the cluster. If your NSX is an early car and has always been in a hot climate (capacitor lifespan is a function of temperature), you may want to consider removing and inspecting the cluster for damage.

That is a lot of 'mays' in the warning so you need to assess your risk tolerance.
 
VSS is the vehicle speed sensor, called VSS1 in manuals. Look on page 23-133 in the 1991 service manual. It sits on top of the transmission casing above where the drive axles are. You can see it from above with a flashlight but need to remove the airbox or other components to gain enough room to remove the 2 bolts holding it on.

You can use https://www.amazon.com/gp/product/B01FAAL7R4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 (or part # 78410-SV4-003) as a cheap replacement, both versions with and without a wiring pigtail included will fit to the stock wiring harness but might be tight depending on your model year. The little peg in the pics ("joint shaft" in the manual) needs to be inserted between the sensor head and the transmission for it to work, the new sensor comes with a new "joint shaft" but you can reuse the old one too.

If you're curious you can take the top 3 screws off the old sensor head and look inside, I'm betting the electrical potting is messed up and smells like burnt plastic.
 
Any idea where I can send my cluster to be looked at and repaired? Nsxe repair website looks like it's under construction
[MENTION=8372]yellow[/MENTION]Scorpian your cluster needs to be rebuilt, there is no doubt. Do it now before it gets worse. It can actually start a fire in your car...you're also going to get good at emptying your wallet

http://www.nsxprime.com/forum/showt...dometer-not-functioning?p=2032940#post2032940

http://www.nsxcb.co.uk/showthread.php?15679-gauge-cluster-fire-issues
 
[MENTION=7588]Briank[/MENTION] appears to be updating his 90's site, too bad, I like business only CL style sites.

You should start with BrianK because he is local, does great work, and has a long track record of quality. Next would be Heineken, but shipping to the EU is long and expensive. And, finally, T3TEC, and everything will just be overly expensive.
 
Considering the circuit, most likely the case but is the Trip meter also not working?


CEL triggered?
If VSS completely fails, it will trigger the CEL.
However, intermittent or non-open/short circuit status won't trigger it.
You won't be able to activate the VTEC if ECU thinks that you are in neutral or less than 5kph/3mph.


Does the Cruise Control still work?
Multiple inputs and conditions so doesn't necessarily tell the VSS failure but at least, you can check.


94 MT so unless you opted for the EPS, you won't trigger the EPS light with the VSS failure.


If you have handheld oscilloscope or even a multimeter, you can do a quick check.

If VSS is fine, time to refurbish your gauge cluster.


Kaz
 
O-scope! That is some serious stuff!

I will admit to having 2 or 3, but I use them so infrequently it takes me longer to remember how to get it working than using!

Problems of having cool tools!

Indeed, modern DSOs with three deep levels on the menu for each control panel button plus so much select-ability in the sampling and triggering set-up that you can turn it into a brick or something that gives you totally weird results. Now where did I store that .pdf of the 600 page user's manual?

I keep my old analog scope around as a sanity check when I manage to set up the scope in some totally weird manner. I have had to use the default to factory settings feature a couple of times.
 
I'm on it!

Dragged out my giant 'NSX Service Manual 1993' 23-133 now and having a look. Thank you!

VSS is the vehicle speed sensor, called VSS1 in manuals. Look on page 23-133 in the 1991 service manual. It sits on top of the transmission casing above where the drive axles are. You can see it from above with a flashlight but need to remove the airbox or other components to gain enough room to remove the 2 bolts holding it on.

You can use https://www.amazon.com/gp/product/B01FAAL7R4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 (or part # 78410-SV4-003) as a cheap replacement, both versions with and without a wiring pigtail included will fit to the stock wiring harness but might be tight depending on your model year. The little peg in the pics ("joint shaft" in the manual) needs to be inserted between the sensor head and the transmission for it to work, the new sensor comes with a new "joint shaft" but you can reuse the old one too.

If you're curious you can take the top 3 screws off the old sensor head and look inside, I'm betting the electrical potting is messed up and smells like burnt plastic.
 
This just happened to me. I would get a check engine light, and the car would not let me WOT pass a certain RPM. I ordered the VSS and planning to install it this weekend.
 
I've owned a 91 Nsx for many, many years. All original/stock and about 31k miles. My odometer and trip counter stopped this month. Speedo and other dash items all working. Has anyone had any luck with the VSS lately, or any other fix? I've though of investing the money is a dash rebuild given the discussions, but finding a good shop to do it is likely going to be difficult I'm assuming. Any similar experiences or thoughts appreciated as I'm guessing I'm not alone on this.
 
If you do not have a CEL indicating an ECU error and the cruise control works, then its 'probably' not the VSS causing the problem. Since you are in North America, NSXe-repair is probably your bets bet for the cluster repair if you cannot do it yourself.
Email Brian K to confirm the details.
 
If you do not have a CEL indicating an ECU error and the cruise control works, then its 'probably' not the VSS causing the problem. Since you are in North America, NSXe-repair is probably your bets bet for the cluster repair if you cannot do it yourself.
Email Brian K to confirm the details.
Thanks, I really appreciate your input...from one Old guy to another. lol I've owned the car almost it's entire life having bought it from the original owner with only a few miles on it. I didn't expect an odometer to not work on an Acura. I've owned other Acura and Honda products without incident, but it is over 30 years old.

If the cruise is not working, does that put the VSS back into play? I have to think as I may not have tried that. It's not something i've used very often given I have a manual car, and I haven't taken it on long drives. Also, what is your opinion on the fire hazards noted above? Is this something typically after the car is driven and is hot, or is it strictly an electrical issue that can be an issue if the car is cold?
 
Failure of the cruise to operate would be a symptom of VSS failure. But, that symptom can have multiple causes with VSS failure being just one of them. Complete failure of the VSS (totally open circuit or short circuit) should also cause the CEL to illuminate. However, like Westley in the Princess Bride it can be only 'mostly dead' which may not trigger a CEL
(can't resist that reference!)
Using the diagnostic service check connector would trigger a 1-7 blink display if the VSS is completely dead. Its worth checking to see if there is a 1-7 stored error code.

If the CEL is illuminated and you have a 1-7 error code and the cruise control is dead, then it is worth checking the VSS. Not the easiest thing to get at. Be aware that the 1991 - 1992 VSS is an orphan (different part # than the later VSS). Search and you can find them for less than $100

Yours is a 5 speed manual because I believe there is a second VSS if you have an auto?

If your cruise operates and you don't have a 1-7 error code then its probably suck-it-up time and remove the cluster which is definitely a pain in the neck activity for this old guy. Purchase a large package of Robax Platinum!

As an observation, doing the capacitor replacement on a 1991 cluster would never be a bad thing and might be a selling feature at some future undetermined date..
 
Thx much, yes 5 speed car. That's kind of what i'm thinking with the rebuild. It's a cherry car, and i've owned it for a long time and got in when prices were near the bottom. It would be a worthwhile investment in all likelihood.
 
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